Home / Summaries / BFI - Laboratory Assignments / animals-symmetry-layers

Lab 7 - Animal Diversity 1: Invertebrates

Q: What are sponges known as and why?

Sponges (Phylum Porifera) are known as 'basal animals' as they do not contain any true tissues and have a very basic body plan.

47 important questions on Lab 7 - Animal Diversity 1: Invertebrates

What are the stinging cells on a cnidarian called?

They are called cnidocytes and they are present on the body and tentacles

Are earthworms dioecious (two separate genders) or hermaphroditic?

Earthworms are hermaphroditic.

What is a tissue in the context of animal body plans?

A tissue is a collection of specialized cells that is separated from other groups of cells by membranous layers.

How does the earthworm's digestive system differ from the flatworm's?

Earthworm's digestive system differ from flatworms because earthworms have a complex digestive system while flatworms have an incomplete digestive system.

What are examples of animals that do not contain any true tissues?

Examples of animals that do not contain any true tissues (ex., sponges).

Differentiate between an open and closed circulatory system. Which do earthworms have? Planaria?

Open circulatory systems have hemolymph in the body cavities. Closed circulatory systems keep blood within the vessels, and earthworms are an example of this. However, planaria have no formal circulatory system.

How does the formation of tissue layers occur in animals?

The formation of tissue layers occurs embryonically, with layers form as the embryo develops.

What are the specific layers of tissue that form during embryonic development?

These germ layers include the ectoderm, a layer covering the surface of the embryo, the endoderm, the innermost germ layer, and the mesoderm, which fills in the space between the ectoderm and the endoderm.

What are sponges known as and why?

Sponges (Phylum Porifera) are known as "basal animals" as they do not contain any true tissues and have a very basic body plan.

How can animals be separated into groups based on germ layers?

Animals can be separated into groups based on the number of germ layers present, diploblastic animals have two layers, while three layers are found in triploblastic animals.

How many species of animals have been identified on earth to date?

To date, there have been approximately 1.3 million species of animals identified on earth, ranging from corals to insects to mammals.

How do sponges feed?

Sponges are suspension feeders; they draw water into their internal cavity (spongocoel) through multiple perforations in their body and expel the water through their osculum, filtering out any food particles.

What type of symmetry do all triploblastic animals have?

All animals with bilateral symmetry are triploblastic.

How many Porifera species are there and what do they contain for protection?

There are about 5500 Poriferans, most containing spicules for protection, which are small, sharp, silica structures.

Which animals are examples of diploblastic animals?

Diploblastic animals include cnidarians and comb jellies.

How is a body plan defined?

A body plan is defined as the morphological and developmental traits within an individual.

What are the different body plans of sponges?

Sponges have three different body plans: ascon, sycon, or leucon.

What is one trait used to organize animals into groups?

One such trait is symmetry.

Describe the thickness of the walls in different sponge body plans.

The ascon shape has the thinnest walls, the sycon has wider walls, and the leucon has the thickest body with many chambers and canals.

What type of symmetry does a sea anemone exhibit?

A sea anemone is an example of an animal with radial symmetry or bilateral symmetry.

What is one of the defining body plan features in addition to symmetry?

The presence of a body cavity, also known as a coelom.

How many known species of cnidarians are there?

There are over 10,000 known species of cnidarians.

In an animal with bilateral symmetry, how many planes of symmetry are there?

In an animal with bilateral symmetry, there is only one plane of symmetry.

What are choanocytes and amoebocytes specialized for?

Choanocytes (collar cells) are specialized cells that have flagella to trap food particles and amoebocytes (specialized cells) that engulf the food by phagocytosis.

How can an animal with bilateral symmetry be described?

An animal with bilateral symmetry can be described using two axes of orientation; top to bottom and front to back.

Describe the body plan of cnidarians.

The body plan of cnidarians is very basic, and has remained unchanged for millions of years.

How do sponges reproduce sexually?

Sexually, the sperm are released into the water, and a specialized cell called a choanocyte is used by another sponge to pick up the sperm. Then the choanocyte cell turns into a carrier cell which then delivers the sperm to the egg.

What must a coelom have arisen from to be considered a "true" coelom?

In order to be considered a "true" coelom, it must have arisen from mesoderm.

What is the function of the tentacles in cnidarians?

The tentacles are used for feeding and protection and for movement in some species.

How do sponges reproduce asexually?

Sponges reproduce asexually by fragmentation, budding, or releasing a hardy and dormant cell clusters which are called gemmules in harsh and cold conditions.

What is the bottom of the animal known as?

The bottom is known as the ventral side.

What are diploblastic animals that contain a coelom considered to have?

Therefore, diploblastic animals that contain a coelom are considered to have a pseudocoelom.

What is the hypostome in cnidarians?

The hypostome is located central to the tentacles and has a mound of tissue that expands and contracts to control the opening and closing of the mouth.

What is the front of the animal known as?

The front of the animal is known as the anterior end.

What are animals with a true coelom known as?

Animals with a true coelom are known as coelomates.

What are the two forms of cnidarians?

There are two forms of cnidarians, sessile polyps which adhere to substrates and motile medusa which travel in the water column.

What are animals with a pseudocoelom known as?

Animals with a pseudocoelom are known as pseudocoelomates.

How many germ layers does a hydra have?

Hydra has two germ layers. They have the epidermis layer and the gastrodermis layer.

What is the formation of a head known as?

The formation of a head is known as cephalization.

What are animals without a coelom known as?

Animals without a coelom are known as acoelomates.

How does a hydra catch and eat food?

Hydra use their tentacles to capture prey, and cnidocytes that are located on their tentacles help to secure their food source. Once the prey has been immobilized, the hydra bring the food to their mouth, ingest it, and it travels to the gastrovascular cavity to be digested.

How many diverse lophotrochozoan phyla does the course textbook cover?

The course textbook goes over six of the diverse lophotrochozoan phyla.

What are the six diverse lophotrochozoan phyla mentioned?

The six diverse lophotrochozoan phyla are the flatworms, rotifers and acanthocephalans, ectoprocts, brachiopods, molluscs, and annelids.

What is the planaria described as in the document?

The planaria is a free-living flatworm that moves about in search of food.

How do planaria ingest food and get rid of undigested food?

Planaria ingest their food by extending a pharynx into their food source, and take away a food particle to be digested. The planaria get rid of their food by regurgitating their food from their pharynx.

What is phototaxis in planaria?

Planaria move away from the light stimulus and therefore experience negative phototaxis.

How does an earthworm crawl?

An earthworm has both circular and longitudinal muscles and crawls by peristalsis. When the longitudinal muscles contract the circular muscles relax and the segment becomes short and fat; conversely when the circular muscles contract the longitudinal muscles relax and the segments become long and thin.

The question on the page originate from the summary of the following study material:

BFI - Laboratory Assignments

View summary

A unique study and practice tool
Never study anything twice again
Get the grades you hope for
100% sure, 100% understanding

Remember faster, study better. Scientifically proven.